Engine starting apparatus



y 1942- D. P. KEARNEY 2,284,431

ENGINE STARTING APPARATUS I Filed July 2, I941 LAM g) m E 1 92 0 -{lhi 11 u) L E L Q N i Q Patented May 26, 1942 ENGINE STARTING APPARATUSDaniel P. Kearney, Birmingham, Mich, assignor to Bendix AviationCorporation, South Bend, Ind., a corporation of Delaware ApplicationJuly 2, 1941, Serial No. 400,845

6 Claims. (01. 290-38) I I This invention relates to engine startingapparatus and more particularly to starters of the inertia type.

Such starters have commonly utilized-a light inertia member, orflywheel, which is actuated by either manual or power means to a veryhigh speed so as to store energy therein, the energy thus stored beingthen transmitted to a.driven or engine-engaging member through areduction gear train or other transmission.

Sometimes when it is attempted to engage the rapidly rotating startermember with a rotatable member of a large engine to be started while thelatter is at rest, only the ends of the teeth of the engaging memberbecome meshed, and there not being sufilcient metal to take up the load,

distortion or breaking of the teeth occurs.

It is therefore one of the objects of the present invention to provide anovel engine starter of the inertia type in which the driving member maybe fully engaged with the rotatable member of the engine to be startedwithout transmitting any load therebetween, and the full load maysubsequently be gradually applied, the full faces of the engaged teethtaking the stress without distortion or breaking.

Another object is to provide an engine starter which is rugged andstrong enough, and of sufficient capacity, to start a reasonably highcompression engine in a dependable and efficient manner withoutrequiring a structure of excessive size, weight, or cost of manufacture.

Another object is to provide an engine starter of the inertia typeembodying a high speed flywheel of considerable mass, and novel meansfor effecting movement of the engine-engaging or driven member toengine-engaging position during the first stage of the flywheelsacceleration.

A further object is to provide a novel engine starter wherein the drivenmember of the starter may be moved into cranking engagement with theengine to be started at a time when the former is subject to little orno driving torque, the driving connection between said member and itssource of energy being adapted to yield after said movement has beencompleted, and to continue to yield while the driving energy is beingcumulatively stored in the driving eledescribed and illustrated in theaccompanying drawing, it is to be expressly understood that the drawingis for the purpose. of illustration only, and is not be construed as alimitation of the scope of the invention, reference being bad for thispurpose to the appended claims.

In the drawing reference character 5 designates the inertia member, orflywheel, numeral 6 its driving motor, and numeral 1 the engineengaging,driven element of the starting apparatus. As shown, the driven element Iis a pinion of the screw-actuated Bendix type that moves axially of itssupporting and driving shaft 8 in order to engage the engine member (notshown); the axial movement being finally arrested by engagement withadjustably positioned stop-nut 9.

The motor 6 has a projecting rotor shaft H, to which is keyed theflywheel 5; and splined thereto is the driving half l2 of a normallydisengaged clutch i2, I3; the driven half l3 being shown as integralwith the screw-shaft 8. A compressible spring I! is interposed betweenthe end faces of the shafts 3 and II, and a yoke l6 straddles the clutchhalf H, as shown. This yoke I6 is shiftable about a pivot shaft Il bymeans i8 and "disposed on opposite sides of the yoke extension 2|.

Means I3 is shown as a spring which normally holds the yoke l6 (hencethe clutch element I!) in the position shown in the drawing, and meansI! is the movable pole-piece, or plunger,

' of a solenoid 23 forming part of a circuit which also includes twoserially connected switches 26 and 21. A source of current is shown at28, and ground connections at 3i, 32, 33, and 34; the last-named beingthe terminal of a coil 36 which surrounds a bi-metallic element 31fixedly mounted at one end and carrying on its free end a contact 38which is adapted to bridge the contacts of switch 26, when the element31 becomes sufliciently heated.

In operation, closure of switch 21 energizes motor 8 and coil 36, thetwo units being in parallel circuits leading from the common source 28.As the motor shaft Ii begins to rotate, the frictional contact withspring I is sufllcient to impart the necessary rotary movement to thedriven shaft 3 to insure completion of the meshing action of the pinionl, as previously described. In the event of end-to-end tooth contact,the spring friction, is augmented by reason of the resulting axialdeflection thereof, wherefore there is assured sufiicient rotation forfull meshing; but, if preferred, the same result may be achieved by useof mesh-facilitating clutch elements on parts II and 8, respectively,which auxiliary clutch elements would be self-disengaging as soon as theend-to-end tooth contact ceased.

When the meshing action is completed, the inertia oi. the engine willresist further rotation of the entire transmission, including the pinionI, and the flywheel 5 will accordingly proceed to run freely, andaccelerate to high speed in response to the continued flow of current ofthe motor. When the parallel current flow through coil 36 has proceededto the point where the heat generated is suflicient to move contact 38on bimetallic element into engagement with contacts 26, current willflow to solenoid 23, to move the yoke extension 2i, adapted to beactuated by the said solenoid 23. This movement is communicated to theclutch member 12 to move the latter into engagement with clutch memberl3, whereupon there is begun the transmission of ertia member, to move.said engine-engaging member to engine-engaging position, and meansresponsive to continued flow of current to drivdriving torque fromthenow energized flywheel t 5 to the now engaged pinion 1.

When the engine has been started by the torque thus transmitted to theengine member (not shown), the resulting acceleration of the pinion I toa speed beyond that of thestarter driven shaft 8 causes the pinion to bereversely' threaded back to the position indicated in Fig. 1. Meanwhilethe release of the switch 21 permits the contact element 31 to cool on,whereupon switch 26 is unbridged, and spring l8 acts to return theclutch member i2 to the disengaged position (shown).

By the use of this novel clutch control, the driven member of thestarter may be engaged with. the engine member without any danger ofinjury to the teeth of the engagingjaws, and

It will be obvious that the invention is not' limited to the form shownin the drawing, but 'is capable of a variety of mechanical embodiments.Various changes, which will now appear to those skilled in the art, maybe made in the form, details of construction, and arrangement of theparts without departing from the spirit of the invention, and referenceis therefore to be had to the appended claimsfor a definition of thelimits of the invention. I

What is claimed is:

1. In combination with an engine startin inertia member rotatable tohigh speed to store energy, an engine-engaging member operable by saidinertia member, means for rotating the inertia member, said meanscomprising a source of current, an electric motor, and a circuit fromsaid source to said motor, means responsive to ably connect said inertiamember with said englue-engaging member, for transmission thereto 0! theenergy stored in said inertia, member.

' 2. In combination with an engine starting inertia member rotatable tohigh speed to store energy, an engine-engaging member operable by saidinertia member, means for rotating the inertia membensaid meanscomprising a source of current, an electric motor, and a circuit fromsaid source to said motor. means responsive to initial flow of currentfrom said source, and the resulting initial rotation of said motor andinertia member, to move said engine-engaging member to engine-engagingposition, and delayed action means for causing torque transmission tosaid engine-engaging member from said inertia member only after thelatter has ac celeratcd to a predetermined degree.

3. In combination with an engine starting inertia member rotatable tohighspeed to store energy, an engine-engaging member operable by saidinertia member, means for rotating the inertia member, said meanscomprising a source of current, an electric motor, and a circuit fromsaid source to said motor, means responsive to initial flow of currentfrom said source, and the resulting initial rotation'of said motor andinertia member, to move said engine-engaging member to engine-engagingposition, and delayed action means for causing torque transmission tosaid engine-engaging member from said inertia member only after theengine-engaging member has moved into full engine-engaging position 4.In combination with an engine starting inertia member rotatable to highspeed to store energy, an engine-engaging member operable by saidinertia member, and heat responsive means for causingtorque transmissionto said engineengaging member from said inertia member only after thelatter has been energized for a period of time sufficient for said heatresponsive means to become heated to a predetermined degree.

initial flow of current from said source, and the 5. In combination withan engine starting inertia. member rotatable to high speed to storeenergy, an engine-engaging member operable by said inertia member, meansfor moving said en- 7 gine-engagin member to engine-engaging position,and heat responsive means for causing torque transmission to saidengine-engaging- .energy, an engine-engaging member operable by saidinertia member, means for moving said engine-engaging member toengine-engaging position, and heat responsive means for causing torquetransmission to said engi e-e g member from said inertia member, onlyafter the engine-engaging member has moved into full engine-engagingposition.

DANIEL P. KEARNEY.

